Automatic draft controller



E. z. BURNS Au'rouuc 1mm cou'monuan June 30, 1925 Filed 1m 3. 1923 4 Sheets-Shea! 1 INVENTOR 64m 9, M M. A ITORm June 30, 1925.

E. Z. BURNS AUTOMATIC DRAFT CONTROLLER 4 she ets 'iheet 2 Filed Aug. 5, 1923 INVENTOR M}.@m4

ATTORNEY maul June 30, 1925.

AUTOIATIC DRAFT CONTROLLER Filed Aug; 5, 1923 4 Sheets-Sheet 3 A'lTORNI-I 7 1,543,983 E. z. BURNS June 30, 1925.

E. z. BURNS AUIOIATIC DRAM CONTROLLER Filed Aug. 3. 1923 4 Shoots-Shoot 4- f Patented June 30, 1925.

UNITED STATES 1,543,983 PATENT OFFICE.

ELMER Z. BURNS, OF MADISON, NEW JERSEY, ASSIGNOR TO THERMOG'EN EQUIPMENT COMPANY, INC., A CORPORATION OF NEW YORK.

AUTOMATIC DRAFT OONTROL LER.

To all whom it may concern:

Be it known that 1, Emma Z. Bonus, a citizen of the United States, residing in Madison, Morris County, State of New Jersey, have invented certain new and useful Improvements in Automatic Draft Controllers, of which the following is a specification.

The present invention has relation to certain improvements in the construction and arrangement of automatic draft controlling apparatus of the type described and claimed in United States Patent to Burns and Keiller, Number 1,433,446 dated October is 24th, 1922. The objects and advantages of the improvements forming the subject matter hereof will be set forth in connection with the description of said improvements in this specification. I These improvements are illustrated in the accompanying drawings where-in. Figure 1 is a. front elevation of a complete machine embodying the improvements herein claimed,

Figure 2 is a diagram of the electrical 26 connections, Figuresti and 4 are side elevations of one of the three point switches in the on and off positions respectively, F igureo is a rear view of one of these switches, Figure 6 is a top view of, the same, Figure 7 is a front elevation of the main switch lever, Figure 8 is a. long'tudinal'sectional view of the same, Figure 9 is a front elevation of the row of primary circuit closers for the motor, Figure 10 is a topview of the same,

.15 Figure 11 is a cross sectional view of the same on the line 11-11 in Figure 9, and Figure 12 is a side elevation of side bracket on the main frame, showing the preferred mode of mounting the damper- 40 actuating levers thereon.

In Figure 1, the main frameis shown at 10, and attached at one side thereof is the bracket 11 upon which is mounted a revolubie shaft 12. At 13 is shown a portion of the lever intended to operate the damper or other draft regulator, which maybe of any well known character as stated in said patent to Burns and Keiller. This lever 13 is fixed to the shaft 12, and the shaft can M be revolved for operation of the damper or its equivalent, by meams of a second lever 14, preferably slotted-at its upper-extremity as shown at 15. As in said Burns and Keiller patent, the

impelling means proper preferably takes the form of a threaded bar 16, mounted for longitudinal movement, and driven back or forth by a worm wheel 17 driven by the reversible electric motor 18. The end of this impelling bar 16jcarries a pin 19 which 60 passes through the slot on the lever 14, and serves to transmit motion to said lever. The impelling bar 16 corresponds to the like element shown at '12 in the Burns and Keiller patent, and is mounted and made to 65 move as therein described. This bar carries a roller 20 corresponding to the roller 81 in the Burnsfand Keiller patent.

- ,The main switch lever 21 is pivoted at 22 and corresponds functionally with the lever 25 of the Burns and Keiller patent. At its lower end it is provided with a curved sector 23, carrying pins 24, which operate the reversing switch shown at A in Figure 2, all ina manner fully described in the Burns 75 and Keiller patent.

The means whereby changes in steam pressure produce movements of the lever 21 comprise the pressure piston 25, the main pressure balance arm 26. and accessory devices, all as found in the Burns and Keiller patent. Figures 7 and 8 show the preferred means whereby. small movements of the balance arm 26 are made to produce a relativeliy Wide swinging movement of the lever 21.

hese means comprise a slender connecting bar 27 pivot-ally connected at 28 with the balance arm 26 and similarly connected with an offset from the lever 21 very close the fulcrum 22, as shown at 29. The upper end of the lever 21 carries the roller 30which operates the primary circuit closing switches in the following manner.

Inv Figures 1, 9 and 10, five of these primary circuit closing switches are shown, corresponding to the switches 49 in the Burns and Keiller patent. These switches are carried on an insulating base 31, andpreferably comprise two normally separated and mutually insulated springs 32, 33, carrying spark-resisting points 34, at their free extremities. The spring 32 of each switch carries a 7 projection 36 passing upward through a curved track 37 over which rolls the roller 30 on the lever 21. It will be clear that, as the roller 30 moves over the track 37 (struck on an arc whose center is the fulcrum 22 of the lever 21) this roller .willdepress the upper s ring 32 of each of the circuit closing switclies in turn, therehr bringing the points 3st and 35 together and closing circuit at each switch in turn as hereinafter described.

At B in Figure 1 is shown a row of circuit preserving relay magnets corresponding to those shown at 50 in the Burns and Keiller patent. The connections for these are shown in Figure 2.

Figures 23, 4-, 5 and (i show the details of the imprmied three-point switch which I have substituted for the two point circuit hr al-zing switches 73 to T9 of the Burns and tiller patent. {in important difference between the arrangement of these switches as compared with those of the l'lurns and lieiller patent that in the present construction all the switches are normally connected in series with each other, while in the liurns and Keillor patent each tch is imlependent of the others. The

tage of this change will appear herein the present construction, as in that of liurns and lZeiller, the circuitbreaking switches are mounted on a ha 38, parallel to the impelling bar 16; and these switcacs are made adjustable as to their relative positions, being slidable along their support. The reasons for this adjustabilit-y are fully escril ed in the Burns and Keillor nt. For this purpose, each switch coma frame held adjustably on the i 38 by a clamping plate 1-0 and screws 11.

The series circuit through these switches is maintained through two side contact pieces, and 13, on the uprightpart of each frame These side contact plates have extensions curving around to the back of the frame 88 and making contact with successive sections of the series wire Qttt, as plainly shown in Figures 3, 4: and 5.

The branch contact of each switch preferably comprises leaf springs 15 fixed on the top of the frame 88, and connected permanently each with a wire leading to a separate circuit-closing switch (see Figure 2 The movable contact of each switch is preferably a bent metal plate are, the top of which is furnished with an extension -17, which is closely embraced by the springs when the plate 16 is in its upper position (Figure 3). In this position, the side lips l8 make contact on opposite sides with the series contacts and 43 (best shown in Figure 6). Consequently in its upper position, where it is held by the friction of the contacts 42 and 43, the plate 46 acts to place all three fixed contacts 42, 13 and 1-5 in electric connection. lvhen in lower position, however, the three contacts are all isolated from each other (see Figure 4).

The up and down movement of the movable switch member 46 is preferably acznplished as follows. A plate 49, fixed on the switch frame serves as a guide for an arm 50 fixed on a slidably plunger 51 carrying av roller or wheel 52, and passing down through the bottom of the frame. A spring 53, attached to the arm 50, tends to pull it and the plunger 51 downward. A swinging hammer 5t is pivotally supported at one end in cars 55 on the arm 50, and a spiral spring 56 has one end fixed to the plate 49 and the other to the free extremity of the hammer 54. The scope of movement of the plunger 51, arm 50 and cars 55 is such that at the top and bottom of their travel the fulcrum of the hammer 5% is on opposite sides of the point of attachment of the spring 56 to the plate e19. (See Figures 3 and l.)

The result of this construction is that, when the plunger 51 is lifted, the hammer 5 1 is swung rapidly and suddenly upward so as to strike the upper horizontal portion of the plate 46, which throws said plate into the closed circuit position shown in Figure 3. Opposite movementof the plunger causes a similar quick downward blow on the plate 46, which opens circuit, as in Figure 1. As shown in Figure 1 the roller 20 on the impelling bar 16 travels along under these switches and raises the plunger-s 51 singly in succession. As soon as the roller passes a switch, the circuitthere made is broken by the falling of the plunger 51, caused by the tension of the spring 53.

Bearing in mind the correspondence of the various parts above described with the parts of the Burns and Keiller device afore mentioned, it will now be easy to understand the mode of operation of the entire device, which I shall now describe with particular reference to Figures 1 and 2.

The row of circuit making switches is shown in Figure 2 having the form indicated in the Burns and Keille-r patent, and it is to be understood that such switches may be used in the present connection, but the form of switch already described with reference to Figures 9, 10 and 11 is preferred. Vhichever form is used it will be understood that a. temporary closure of circuit is effected at each switch in succession, as the end of the main lever 21 passes such switch.

Any reversible motor 18 may be used to operate the impelling bar 16 to move the damper or equivalent device. In Figure 2 is indicated diagrammatically a motor having a series field magnet coil 5'7 and a shunt coil 58. The armature is indicated at 59.

Assuming that there has been a fall of pressure which has caused the lever 21 to tilt anti-clockwise in Figure 2, closing circuit in the middle switch of the series as it passes the same, as indicated in Figure 2. Current will then enter on the main wire 60 and flow as follows-partly through the shunt coil 58, directly to the outgoing wire 61-the remainder through the series field magnet coil 57 wire 62 to reversing switch A, magnet coil 63, wire 44, circuit-breaker 64, wire 65 to the middle circuit closing switch 66, wire 67 to relay primary 68, wire 69, resistance 70, wire 71, armature 59, wire 72 to reversing switch A and thence to the out oing wire 61.

fins at once starts the motor 18 so as to move the impelling rod and the roller 20 to the right in Figure 2. This may be assumed to open the damper or otherwise cause increase of draft to compensate for the drop in pressure. At the same time the relay 68 closes the switch at 73 to maintain closure of the motor driving circuit in a manner described in the Burns and lieiller patent. Assuming that the lever 21 does not close any other switch, the motor 18 will be brought to rest as soon as the roller 20 reaches the circuit-breaker 64, as is made clear from the Burns and Keiller patent.

All the description of operation of the Burns and Keiller circuit-breakers and their relation to the movements of the main switch lever and circuit-closers operated thereby applies to the present construction, save that the three point switches herein described connected as shown with the series wire 44 1S novel, and makes it necessary for the current to pass through all the switches on one side of that which is connected to the particular circuit closer which has last operated. This is the opposite side to the correspondin position of the roller 20.

The 0 ject of this improvement is to prevent a possibledriving of the im lling device all the way to the limit un er certain accidental conditions when this would not be desirable.

In the form shown in Burns and Keiller, wherein each circuit-breaker is in a branch independent of all the others, it is conceivable that the lever 21 (numbered 25 in Burns and Keiller) might be impelled to left and then to right in quick succession by a surge of steam pressure, and this might occur in such a position as to operate one and the same circuit closer a second time and continue its second swing far enough to o erate another circuit-closer, before the rol er 20 (or 81 in Burns and Keiller) had reached the first circuit-breaker in its path. The result of this would be that circuit would be closed through a circuit breaker behind the moving roller on the impelling bar. Obviously, under these conditions there would be nothing to stop the impelling bar until the roller reached one of the limit switches, shown at 73 and 79 in the Burns and Keiller patent.

By using the series connection shown herein, if the roller 20 failed to open circuit at 64 (when moving toward the right in Figure 2) it would certainly open circuit at the next switch to the right. I have shown limiting two-point switches at 74 and 75 in Figure 2, but they are not strictly necessary in this arrangement.

Various changes may be made in the construction and arran ement of this apparatus without departing from the scope of my invention which is not limited to the details herein shown and described.

What I claim is 1. In an automatic draft controlling apparatus driven by an electric motor, a succession of circuit breakers each provided with a reciprocating plunger adapted to operate it, electrical connections normally connecting said circuit breakers in series with said motor, and automatic means for operating said circuit breakers successively, said means comprising a roller adapted to travel along the series of plungers so as to cause operative movement of one plunger at a time.

2. In an automatic draft cont-rolling apparatus driven by an electric motor, a succession of circuit-closing switches, each comprising a depressible spring, and a main switch lever pivotally mounted and having a roller adapted to travel along said succession of circuit-closers so as to depress said springs one at a time in succession.

In testimony whereof I have hereto set my hand on this 1st day of August, 1923.

ELMER Z. BURNS. 

